The .alpha.-(1-methylethyl)-3,4-dimethoxybenzeneacetonitrile is an intermediate useful in the preparation of a drug having coronodilator activity, internationally known as verapamil (INN), described in U.S. Pat. No. 3,261,859.
The synthesis of the .alpha.-(1-methylethyl)-3,4-dimethoxybenzeneacetonitrile has been described in many patents such a U.S. Pat. Nos. 3,415,866, 3,997,608 and 4,593,042, Canadian Patent 986946, Unexamined Japanese Patent Publication No. 78092732, European Publication No. 0165322 and Hungarian Patent HUT 032064.
The primary method, described in the Canadian and Hungarian Patents, in U.S. Pat. No. 4,593,042 and in the Unexamined Japanese Publication, consists in the alkylation of the homoveratronitrile by means of an isopropyl halide, in the presence of many kinds of alkaline agents and in different solvents. In U.S. Pat. Nos. 3,415,866 and 3,997,608, homoveratronitrile is reacted with acetone in the presence of sodium ethoxide and the resulting isopropylidene derivative is catalytically hydrogenated. Finally, in the above mentioned European Publication, the nitrile is obtained by reacting the .alpha.-(1-methylethyl)-benzylchloride with sodium cyanide.